o ldlinux_v4.[bss|sys] have been renamed from ldlinux.[bss|sys] found in syslinux-4.07/core/
o ldlinux_v5.[bss|sys] have been renamed from ldlinux.[bss|sys] found in syslinux-5.10/core/
http://www.kernel.org/pub/linux/utils/boot/syslinux/